Iron silicide sputtering target and method for production thereof

ABSTRACT

Provided is an iron silicide sputtering target in which the oxygen as the gas component in the target is 1000 ppm or less, and a manufacturing method of such iron silicide sputtering target including the steps of melting/casting high purity iron and silicon under high vacuum to prepare an alloy ingot, subjecting the ingot to gas atomization with inert gas to prepare fine powder, and thereafter sintering the fine powder. With this iron silicide sputtering target, the amount of impurities will be reduced, the thickness of the βFeSi 2  film during deposition can be made thick, the generation of particles will be reduced, a uniform and homogenous film composition can be yielded, and the sputtering characteristics will be favorable. The foregoing manufacturing method is able to stably produce this target.

BACKGROUND OF THE INVENTION

The present invention relates to an iron silicide sputtering targethaving transition-type semiconductor characteristics and suitable forforming a βFeSi₂ thin film to be used as an optical communicationelement or solar battery material, and the manufacturing method of suchiron silicide sputtering target.

Although silicon has been the most popular material conventionally asthe LSI semiconductor material, a compound semiconductor ofindium/phosphorus, gallium/arsenic or the like is being used for opticalcommunication (LE/LED).

Nevertheless, indium has an extremely short life span as a resource, andit is said that it can only be mined for another 20 years or so.Further, arsenic is well known as an element having strong toxicity.Thus, there is no choice but to say that the optical communicationsemiconductor materials being widely used today have significantproblems for use.

In particular, the semiconductor element of gallium/arsenic being usedin cell phones with a short product-life cycle includes arsenic havingstrong toxicity, and this is causing a significant problem regarding thewaste disposal thereof.

Under the foregoing circumstances, it has been discovered that βFeSi₂possesses transition-type semiconductor characteristics, and is beingnoted as a favorable optical communication element and solar batterymaterial. The greatest advantage of this βFeSi₂ is that the respectiveconstituent elements are extremely abundant on earth, and that there isno danger of toxicity or the like. Thus, these materials are known asenvironmentally friendly materials.

Nevertheless, this βFeSi₂ is not free of problems, and, at present,technology for preparing high-quality material comparable to compoundsemiconductors of indium/phosphorus, gallium/arsenic or the like has notyet been established.

Currently, as technology for forming an FeSi₂ thin film, proposed istechnology for forming βFeSi₂ by sputtering an Fe target and forming anFe film on a Si substrate, and thereafter generating a silicideformation reaction between Si as the substrate material and the Fe filmby heating the deposited Si substrate.

Nevertheless, there are problems in that, with this method, since thesubstrate needs to be heated at a high temperature for a long periodduring deposition and during annealing, there will be limitations on thedevice design, and that it is difficult to form a thick βFeSi₂ filmsince the silicide formation reaction is based on the diffusion of Sifrom the substrate.

As a method similar to the above, proposed is a method of accumulatingFe on the Si substrate while maintaining the substrate at a temperaturein which Fe and Si will react; that is, at 470° C., but this method alsoencounters problems similar to those described above.

Further, as another method, proposed is a method for forming a βFeSi₂film by separately sputtering the Fe target and Si target; that is,performing co-sputtering so as to laminate several layers of the Felayer and Si layer, and heating this to generate a silicide formationreaction.

Nevertheless, with this method, there are problems in that thesputtering process will become complex, and that it is difficult tocontrol the uniformity of the thickness direction of the film.

Each of the foregoing methods is based on the premise of performingannealing after depositing Fe on the Si substrate, and, with thesemethods that require heating at high temperatures for a long period, aproblem has been noted in that the βFeSi₂, which was formed in a filmshape, becomes aggregated into an island shape together with theprogress of annealing.

Further, with the foregoing methods, since the Fe target is aferromagnetic body, it is difficult to perform magnetron sputtering, andit is thereby difficult to form an even film on a large substrate.Therefore, an even βFeSi₂ film with few variations in the compositionresulting from the subsequent silicide formation could not be obtained.

Moreover, although a proposal of a target (mosaic target) in which Feand Si blocks are disposed in a prescribed area ratio has also beenmade, since the sputtering rate of Fe or Si, whichever is sputtered,will differ considerably, it is difficult to deposit a prescribed filmcomposition on a large substrate, and it was not possible to prevent thearcing or generation of particles at the bonding interface of Fe and Si.

Conventionally, as technology employing FeSi₂, technology relating tothe manufacturing method of a thermoelectric material including thesteps of forming capsule particles by covering the nuclear particles ofFeSi particles with Si particles of a prescribed weight ratio,performing current-conduction sintering to the powder aggregate of thecapsule particles, and generating an FeSi₂ intermetallic compound hasbeen disclosed (e.g., refer to Japanese Patent Laid-Open Publication No.H5-283751).

Further, a manufacturing method of βFeSi₂ including a step ofpulverizing and mixing raw material powder containing Fe powder and Sipowder, a step of molding the pulverized and mixed powder, and a step ofsintering the molded material has been disclosed (e.g., refer toJapanese Patent Laid-Open Publication No. H6-81076).

Moreover, a manufacturing method of iron silicide thermoelectricmaterial including the steps of mixing ferrosilicon and iron powder, andsubsequently performing pressure sintering thereto at a sinteringtemperature of 900 to 1100° C. under an inert atmosphere has beendisclosed (e.g., refer to Japanese Patent Laid-Open Publication No.H7-162041).

Further, a manufacturing method of raw material powder for an FeSi₂thermoelectric conversion element including the steps of mixing aprescribed amount of transition metal powder to fine powder obtained viajet mill pulverization with inert gas so as to easily obtain fine powderhaving a low residual oxygen content and an average grain size ofseveral μm or less, performing spray granulation thereto with a spraydryer, and subsequently performing pressing and sintering thereto hasbeen disclosed (e.g., refer to Japanese Patent Laid-Open Publication No.H10-12933).

Moreover, a metallic silicide luminescent material in which a β-ironsilicide semiconductor element, which is a metallic silicidesemiconductor particle having a grain size on the order of nanometers,is dispersed in a particle shape in the polycrystalline silicon has beendisclosed (e.g., refer to Japanese Patent Laid-Open Publication No.2000-160157).

SUMMARY OF THE INVENTION

The present invention was devised in order to overcome the foregoingproblems, and an object thereof is to provide an iron silicidesputtering target in which the amount of impurities will be reduced, thethickness of the βFeSi₂ film during deposition can be made thick, thegeneration of particles will be reduced, a uniform and homogenous filmcomposition can be yielded, and the sputtering characteristics will befavorable, as well as the method of stably manufacturing such an ironsilicide sputtering target.

The present invention provides:

-   1. An iron silicide sputtering target, wherein the content of oxygen    as the gas component in the target is 1000 ppm or less;-   2. An iron silicide sputtering target according to paragraph 1    above, wherein the content of oxygen as the gas component in the    target is 600 ppm or less;-   3. An iron silicide sputtering target according to paragraph 2    above, wherein the content of oxygen as the gas component in the    target is 150 ppm or less;-   4. An iron silicide sputtering target according to any one of    paragraphs 1 to 3 above, wherein the content of carbon as the gas    component in the target is 50 ppm or less, the content of nitrogen    as the gas component in the target is 50 ppm or less, the content of    hydrogen as the gas component in the target is 50 ppm or less, and    the content of sulfur as the gas component in the target is 50 ppm    or less;-   5. An iron silicide sputtering target according to any one of    paragraphs 1 to 4 above, wherein the relative density of the target    is 90% or more;-   6. An iron silicide sputtering target according paragraph 5 above,    wherein the relative density of the target is 95% or more;-   7. An iron silicide sputtering target according to any one of    paragraphs 1 to 6 above, wherein the average crystal grain size of    the target texture is 300 μm or less;-   8. An iron silicide sputtering target according to paragraph 7    above, wherein the average crystal grain size of the target texture    is 150 μm or less;-   9. An iron silicide sputtering target according to paragraph 8    above, wherein the average crystal grain size of the target texture    is 75 μm or less; and-   10. An iron silicide sputtering target according to any one of    paragraphs 1 to 9 above, wherein the target texture is substantially    a ζ_(α) phase, or the primary phase is a ζ_(α) phase.

The present invention also provides:

-   11. A manufacturing method of an iron silicide sputtering target,    including the steps of melting/casting high purity iron and silicon    under high vacuum to prepare an alloy ingot, subjecting the ingot to    gas atomization with inert gas to prepare fine powder, and    thereafter sintering the fine powder;-   12. A manufacturing method of an iron silicide sputtering target    according to any one of paragraphs 1 to 10 above, including the    steps of melting/casting high purity iron and silicon under high    vacuum to prepare an alloy ingot, subjecting the ingot to gas    atomization with inert gas to prepare fine powder, and thereafter    sintering the fine powder;-   13. A manufacturing method of an iron silicide sputtering target    according to paragraph 11 or paragraph 12 above, wherein the high    purity iron and silicon are melted with the cold crucible melting    method employing a water-cooled copper crucible;-   14. A manufacturing method of an iron silicide sputtering target    according to any one of paragraphs 11 to 13 above, wherein the fine    powder is sintered via hot pressing, hot isostatic pressing or spark    plasma sintering; and-   15. A manufacturing method of an iron silicide sputtering target    according to any one of paragraphs 11 to 14 above, wherein [the fine    powder] is heated under a hydrogen atmosphere and subject to    decarbonization/deoxidization processing, subject to degasification    processing under a vacuum atmosphere, and thereafter sintered.

DETAILED DESCRIPTION OF THE INVENTION

Although the iron silicide sputtering target of the present invention isrepresented with the molecular formula of FeSi₂ unless otherwisespecified, this includes the scope of FeSix (x: 1.5 to 2.5).

Further, the iron silicide sputtering target used in this descriptionmeans every type of iron silicide comprising the property ofsemiconductors, and iron silicide containing iron silicide as itsprimary component and small amounts of other additive elements, and thepresent invention covers all of the above.

With the iron silicide sputtering target of the present invention, thecontent of oxygen as the gas component is 1000 ppm or less, preferably600 ppm or less, and more preferably 150 ppm or less. As a result, thegeneration of particles during sputtering can be suppressed, and auniform and homogenous film composition can be yielded.

Further, from the perspective of similar characteristic, it is desirablethat the content of carbon as the gas component in the target is 50 ppmor less, the content of nitrogen as the gas component in the target is50 ppm or less, the content of hydrogen as the gas component in thetarget is 50 ppm or less, and the content of sulfur as the gas componentin the target is 50 ppm or less. Incidentally, a gas component means theelement detected in a gas state upon performing quantitative analysis.

Moreover, when the relative density of the target is 90% or more,preferably 95% or more, and the average crystal grain size of the targettexture is 300 μm or less, preferably 150 μm or less, and morepreferably 75 μm or less, arcing and generation of particles can befurther suppressed, and a film having stable characteristics can beobtained thereby.

When the iron silicide target texture is substantially a ζ_(α) phase, orthe primary phase is a ζ_(α) phase; that is, when the phasetransformation to the β phase (semiconductor phase) is suppressed andthe ζ_(α) phase still remains, a stable bias current can be applied tothe target, and plasma density can be increased easily, and thesputtering gas pressure can be kept low. As a result, a superior effectis yielded in that a favorable film with few gas damages can beobtained.

Upon manufacturing the iron silicide sputtering target of the presentinvention, high purity iron of 3N5 (99.95 wt %, hereinafter the same) ormore, preferably 4N or more, and more preferably 4N5 or more, andsilicon of 5N or more are used as the raw materials.

These are melted/cast under high vacuum to prepare an alloy ingot, theseare melted once again and then subject to gas atomization with inert gasto prepare fine powder, and this fine powder is sintered to form asintered body, and this is manufactured into a target to obtain the ironsilicide sputtering target.

Upon melting the high purity iron and silicon, it is desirable toperform this with the cold-crucible melting method employing a copperwater-cooled crucible. With this cold-crucible melting method, incomparison to the ordinarily adopted vacuum induction melting methodemploying an aluminum crucible, the oxidization of the raw materials andmixing of impurities from the crucible can be suppressed, and an ingothaving a uniform composition can be obtained.

When pulverizing the obtained ingot, in comparison to mechanicalpulverizing methods employing a stamp mill or ball mill, since theatomization method employing inert gas is able to rapidly cool, solidifyand pulverize the ingot, spherical fine powder with minimalcontamination (particularly oxidization) and favorable degree ofsintering can be obtained. According to the above, fine powder with ahigh residual ratio of ζ_(α) (also referred to as the αFe₂Si₅ phase orαFeSi₂ phase) (metallic phase) can be obtained.

The obtained fine powder is sintered via hot pressing, hot isostaticpressing or spark plasma sintering. Upon sintering, spark plasmasintering is particularly desirable. According to this spark plasmasintering method, the growth of crystal grains can be suppressed, and ahigh density, high strength target can be sintered. Further, sincesintering can be performed in a short period and this can be cooledrapidly, the phase transformation to the β phase (semiconductor phase)can be suppressed, and a target having a high residual ratio of theζ_(α) phase (metallic phase) can be obtained. If different phases existin the target, the rate of sputtering will differ, and this is notpreferable since this will cause the generation of particles.

Predominately, when a single phase ζ_(α) phase (metallic phase) is used,a stable bias current can be applied to the target, plasma density canbe increased easily, and the sputtering gas pressure can be kept low.Thus, a favorable film with few gas damages can be obtained.

Further, prior to sintering, it is preferable to heat [the fine powder]under a hydrogen atmosphere, perform decarbonization/deoxidizationprocessing thereto, and further perform degasification processingthereto under a vacuum atmosphere. As a result, it is possible to obtaina sputtering target in which the gas components can be eliminated, thegeneration of particles will be reduced, a uniform and homogenous filmcomposition can be yielded, and the sputtering characteristics will befavorable.

EXAMPLES AND COMPARATIVE EXAMPLES

The present invention is now explained in detail with reference to theExamples and Comparative Examples. These Examples are merelyillustrative, and the present invention shall in no way be limitedthereby. In other words, the present invention shall only be limited bythe scope of claim for a patent, and shall include the variousmodifications other than the Examples of this invention.

Examples 1 to 3

High purity Fe having a purity of 3N5 to 5N and high purity Si having apurity of 5N in block shapes were weighed at a prescribed molar ratio,these were melted at 1250 to 1600° C. with a cold-crucible melting unitemploying a water-cooled copper crucible (vacuuming was sufficientlyperformed until the ultimate vacuum prior to heating reached an order of10⁻⁵ torr), and then cast in a mold in a vacuum to prepare an ingot.Upon melting, after foremost melting Fe, Si was gradually added to theFe molten metal and sufficiently alloyed. Moreover, these were alsoalloyed with a vacuum induction melting unit employing a high purityalumina crucible and an arc melting unit.

The ingot obtained pursuant to the above was melted once again, and thiswas atomized in argon gas (gauge pressure of 50 to 80 kgf/cm²) with agas atomization device to prepare spherical alloy powder having adiameter of 300 μm or less.

Powder of a prescribed grain size was sieved from such spherical alloypowder, and sintered for 2 hours in a vacuum atmosphere with hotpressing at 1000 to 1220° C. and a surface pressure of 250 to 300kgf/cm². The surface of the obtained sintered body was ground with aflat-surface grinding machine to remove the contamination layer on thesurface thereof, and an iron silicide target of φ300 mm×5 mm wasprepared thereby.

The raw material purity, composition (Fe:Si) ratio, dissolution method,pulverizing method, sieved grain size, and sintering method of Examples1 to 3 are respectively shown in Table 1.

TABLE 1 Raw Material Dissolution Pulverization Sieved Purity Fe:Si RatioMethod Method Grain Size Sintering Method Example 1 Fe(3N5) 1:2.2 ColdCrucible Ar Gas Atomization Ave.  30 μm HP Example 2 Fe(3N5) 1:1.8 VIMAr Gas Atomization Ave.  31 μm HP Example 3 Fe(4N) 1:2.5 Arc Melting ArGas Atomization Ave.  35 μm HP Example 4 Fe(4N) 1:2.2 Cold Crucible ArGas Atomization Ave.  33 μm HIP Example 5 Fe(5N) 1:2.0 Cold Crucible ArGas Atomization Ave.  18 μm HIP Example 6 Fe(4N) 1:1.8 Cold Crucible ArGas Atomization Ave.  35 μm SPS Example 7 Fe(5N) 1:1.5 Cold Crucible ArGas Atomization Ave.  28 μm SPS Example 8 Fe(4N) 1:2.05 Cold Crucible ArGas Atomization Ave.  45 μm HP (w/deoxidization and heat treatment)Example 9 Fe(5N) 1:2.5 Cold Crucible Ar Gas Atomization Ave. 120 μm HP(w/deoxidization and heat treatment) Example 10 Fe(5N) 1:2.01 ColdCrucible — — HIP Comparative Example 1 Fe(3N5) 1:1.6 VIM Ball Mill Ave. 10 μm HP Comparative Example 2 Fe(3N5) 1:1.6 VIM Ball Mill Ave.  16 μmHP Comparative Example 3 Fe(4N) 1:2.3 VIM Ar Gas Atomization Ave. 160 μmHIP Comparative Example 4 Fe(3N5) 1:2.0 Arc Melting Ball Mill Ave.  12μm HIP Comparative Example 5 Fe(4N) 1:2.0 Arc Melting Ball Mill Ave.  10μm SPS HP: Hot Pressing HIP: Hot Isostatic Pressing SPS: Spark PlasmaSintering VIM: Vacuum Induction Melting

Examples 4 and 5

Hot isostatic pressing was used as the sintering method. The otherconditions were the same as Examples 1 to 3.

As the specific conditions of hot isostatic pressing, the foregoingpowder was vacuum-encapsulated in a soft steel container, and sinteredfor 3 hours at 1150° C. at an atmospheric pressure of 1500. The surfaceof the obtained sintered body was ground with a flat-surface grindingmachine to remove the contamination layer on the surface thereof, and aniron silicide target of φ300 mm×5 mm was prepared thereby.

Details regarding the raw material purity, composition (Fe:Si) ratio,dissolution method, pulverizing method, sieved grain size, and sinteringmethod of Examples 4 and 5 are respectively shown in Table 1.

Examples 6 and 7

Spark plasma sintering was used as the sintering method. The otherconditions were the same as Examples 1 to 3. Details regarding the rawmaterial purity, composition (Fe:Si) ratio, dissolution method,pulverizing method, sieved grain size, and sintering method of Examples6 and 7 are respectively shown in Table 1.

As the specific conditions of spark plasma sintering, the raw materialpowder shown in Table 1 was filled inside a graphite mold and sinteredfor 5 minutes with a pulse current of 8000 A. As a result of employingthe spark plasma sintering method, high density plasma will be generatedat the contact site of the filled particles, and rapid sintering wasenabled.

The surface of the obtained sintered body was ground with a flat-surfacegrinding machine to remove the contamination layer on the surfacethereof, and an iron silicide target of φ125 mm×5 mm was preparedthereby.

Examples 8 and 9

In these Examples, other than the temporary sintered body being subjectto hydrogen processing→vacuum processing, the other conditions were thesame as Example 1 to 3. Details regarding the raw material purity,composition (Fe:Si) ratio, dissolution method, pulverizing method,sieved grain size, and sintering method of Examples 8 and 9 arerespectively shown in Table 1.

A temporary sintered body with a density of 70 to 90% and having openpores was prepared with hot pressing at a sintering temperature of 700to 1000° C., heat treatment was performed to this temporary sinteredbody in a hydrogen gas stream at 900° C. for 5 hours, decarbonizationand deoxidization processing was further performed thereto, anddegasification was subsequently performed via heat treatment in a vacuumatmosphere (order of 10⁻⁴ torr).

Next, this temporary sintered body was sintered with hot pressing. Thesurface of the obtained sintered body was ground with a flat-surfacegrinding machine to remove the contamination layer on the surfacethereof, and an iron silicide target of φ300 mm×5 mm was preparedthereby.

Example 10

This Examples does not use pulverized powder, and obtains a targetmaterial by slicing the vacuum-melted ingot, and subject this to heattreatment. The other conditions were the same as Examples 1 to 3.Details regarding the raw material purity, composition (Fe:Si) ratio,dissolution method, and sintering method of Example 10 are respectivelyshown in Table 1.

After preparing a cast ingot under the same conditions as Examples 1 to3, this ingot was cut with a wire saw, further subject to hot isostaticpressing at 1050° C. and an atmospheric pressure of 1500 so as to reducethe cast defects, and the surface of the obtained sintered body wasground with a flat-surface grinding machine as with the foregoingExamples to remove the contamination layer on the surface thereof, andan iron silicide target of φ150 mm×5 mm was prepared thereby.

Comparative Examples 1 to 3

High purity Fe having a purity of 3N5 to 5N and high purity Si having apurity of 5N in block shapes were weighed at a prescribed molar ratio,these were melted at 1250 to 1600° C. with a high purity aluminacrucible and vacuum induction melting unit. Upon melting, after foremostmelting Fe, Si was gradually added to the Fe molten metal andsufficiently alloyed.

After melting, this was cast in a mold in a vacuum to prepare an ingot.Next, the ingot was cut, roughly pulverized to be approximately 1 mm orless with a stamp mill, and then pulverized for 10 hours with a ballmill.

Upon pulverization, the cylindrical column (diameter of roughly 10 mm,length of 15 mm) of high purity Fe was filled up to ⅓ of the innervolume of the ball mill to become the grinding medium, and, afterplacing the roughly pulverized ingot therein, argon gas was substitutedwithin the mill to prevent oxidization.

Powder of a prescribed grain size was sieved from such spherical alloypowder, and sintered for 2 hours with hot pressing at 1000 to 1220° C.and a surface pressure of 250 to 300 kgf/cm².

The surface of the obtained sintered body was ground with a flat-surfacegrinding machine to remove the contamination layer on the surfacethereof, and an iron silicide target of φ300 mm×5 mm was preparedthereby.

The raw material purity, composition (Fe:Si) ratio, dissolution method,pulverizing method, sieved grain size, and sintering method ofComparative Examples 1 to 3 are respectively shown in Table 1.

Comparative Examples 4 and 5

Other than employing the arc melting method for preparing the ingot, thetarget was manufactured under the same conditions as ComparativeExamples 1 to 3.

The surface of the obtained sintered body was ground with a flat-surfacegrinding machine to remove the contamination layer on the surfacethereof, and an iron silicide target of φ300 mm×5 mm was preparedthereby. The raw material purity, composition (Fe:Si) ratio, dissolutionmethod, pulverizing method, sieved grain size, and sintering method ofComparative Examples 4 and 5 are respectively shown in Table 1.

The oxygen analysis results of the targets of Example 1 to 10, andComparative Examples 1 to 5 are shown in Table 2, and regarding Examples1, 5 and 10, the analysis results of other impurities are shown in Table3.

Further, texture of the target was observed at 17 locations radially,and the average crystal grain size was calculated with the sectionmethod from the texture photograph. Moreover, the density was measuredwith the Archimedes method, and the crystal structure was furtherexamined with XRD. The results are shown in Table 2.

In addition, the targets of Example 1 to 10, and Comparative Example 1to 5 were used to perform DC magnetron sputtering on a 3-inch Si (100)substrate so as to evaluate the sputtering characteristics and filmcharacteristics of the target. The results are similarly shown in Table2.

TABLE 2 Oxygen Relative Density Average Uniformity Particles (ppm) (%)Grain Size (3σ) Quantity/cm² Example 1 820 92.5 112 μm  4.2% 0.3 Example2 680 95.5 150 μm  1.6% 0.5 Example 3 450 96 180 μm  2.3% 1.2 Example 4420 97 123 μm  1.9% 2.5 Example 5 460 93  42 μm  3.1% 0.9 Example 6 11092  96 μm  1.8% 0.5 Example 7 140 97.5  52 μm  3.4% 0.5 Example 8 35095.3  65 μm  1.8% 2.3 Example 9 24 96.5 290 μm  3.2% 1.6 Example 10 40100 560 μm 12.5% 0.6 Comparative Example 1 2300 96  52 μm  3.0% 7.8Comparative Example 2 1800 96 260 μm  2.8% 25.1 Comparative Example 31200 88  36 μm 28.6% 36.3 Comparative Example 4 1500 98  40 μm  1.5%13.3 Comparative Example 5 1600 97  85 μm  0.8% 10.2

TABLE 3 Unit: ppm Example 1 Example 4 Example 10 C 26 13 4 N 18 8 1 H 159 2 S 1 5 1 P 5 <1 1 Cl 59 <1 <1 Mn 6 <0.1 0.2 Cu 8 <1 0.3 Al 3 <0.5 0.3As <1 <1 <1 B 0.5 <1 <1 Bi <1 <1 <1 Ca <2 <1 <1 Cd <0.1 <1 <1 Co 16 15 1Cr <0.5 <0.3 0.3 Mg <0.1 <1 <1 Mo <0.2 <1 <1 Pb 0.5 <1 0.2 Sb 0.5 <1 <1Sn 0.3 <1 <1 Ti <0.1 <1 <1 V <0.4 <1 <1 W 0.3 <1 <1 Zn 1.2 <0.4 <1 Zr <1<1 <1 Te <1 <1 <1 Ag <1 <1 <1 Na <1 <1 <1 K <1 <1 <1 U <0.005 <0.005<0.005 Th <0.005 <0.005 <0.005

As shown in Table 2, in the Examples of the present invention, theoxygen content as impurity was low, the relative density was 90% ormore, the average crystal grain size was 300 μm or less (excluding themelted target of Example 10), the area ratio of ζ_(α) was 70% or more,the evenness (uniformity, 3σ) of the film was favorable, the generationof particles was significantly reduced, and the sputteringcharacteristics were favorable. Further, as shown in FIG. 3, otherimpurities were also significantly reduced.

Meanwhile, in each of the Comparative Examples, the oxygen content washigh, the ratio of βFeSi₂ was also high, and the target showedsignificant generation of particles, and a film that could be peeledeasily was formed. These problems caused the deterioration of thesputtered deposition quality. Moreover, the peak of βFeSi₂ from the XRDmeasurement could not be observed from either the Example or ComparativeExamples.

The iron silicide sputtering target of the present invention yields asuperior effect in that the amount of impurities such as oxygen will bereduced, the thickness of the βFeSi₂ film during deposition can be madethick, the generation of particles will be reduced, a uniform andhomogenous film composition can be yielded, and the sputteringcharacteristics will be favorable. The present invention also yields asuperior effect in that such target can be stably manufactured.

1. A sputtering target, comprising an iron silicide magnetron sputteringtarget having a content of oxygen as a gas component of 1000 ppm orless, a relative density of at least 90%, and a target texture with anaverage crystal grain size of 300 μm or less, said target texture beingsubstantially a ζ_(a) phase, or having a primary phase that is a ζ_(a)phase.
 2. An iron silicide sputtering target according to claim 1,wherein the content of oxygen as the gas component in the target is 600ppm or less.
 3. An iron silicide sputtering target according to claim 2,wherein the content of oxygen as the gas component in the target is 150ppm or less.
 4. A sputtering target according to claim 3, wherein saidgas component of said target includes a content of carbon of 50 ppm orless, a content of nitrogen of 50 ppm or less, a content of hydrogen of50 ppm or less, and a content of sulfur of 50 ppm or less.
 5. Asputtering target according to claim 4, wherein said relative density ofsaid target is at least 95%.
 6. A sputtering target according to claim5, wherein said average crystal grain size is 150 μm or less.
 7. Asputtering target according to claim 6, wherein said average crystalgrain size is 75 μm or less.
 8. A sputtering target according to claim1, wherein said gas component of said target includes a content ofcarbon of 50 ppm or less, a content of nitrogen of 50 ppm or less, acontent of hydrogen of 50 ppm or less, and a content of sulfur of 50 ppmor less.
 9. A sputtering target according to claim 1, wherein saidrelative density of said target is at least 95%.
 10. A sputtering targetaccording to claim 1, wherein said average crystal grain size is 150 μmor less.
 11. A sputtering target according to claim 1, wherein saidaverage crystal grain size is 75 μm or less.
 12. A method ofmanufacturing an iron silicide magnetron sputtering target, comprisingthe steps of melting and casting high purity iron and silicon under highvacuum to prepare an alloy ingot, subjecting the ingot to gasatomization with inert gas to prepare fine powder, and thereaftersintering the fine powder to provide an iron silicide magnetronsputtering target having a content of oxygen as a gas component of 1000ppm or less, a relative density of at least 90%, and a target texturewith an average crystal grain size of 300 μm or less, said targettexture being substantially a ζ_(a) phase, or having a primary phasethat is a ζ_(a) phase.
 13. A method according to claim 12, wherein thehigh purity iron and silicon are melted via a cold crucible meltingprocess employing a water-cooled copper crucible.
 14. A method accordingto claim 13, wherein the fine powder is sintered by one of hot pressing,hot isostatic pressing, and spark plasma sintering.
 15. A methodaccording to claim 14, wherein, before said sintering step, said finepowder is heated under a hydrogen atmosphere, subjected todecarbonization and deoxidization processing, and subjected todegasification processing under a vacuum atmosphere.
 16. A methodaccording to claim 12, wherein the fine powder is sintered by one of hotpressing, hot isostatic pressing, and spark plasma sintering.
 17. Amethod according to claim 12, wherein, before said sintering step, saidfine powder is heated under a hydrogen atmosphere, subjected todecarbonization and deoxidization processing, and subjected todegasification processing under a vacuum atmosphere.
 18. A sputteringtarget, comprising: a magnetron sputtering target body consisting ofiron silicide of a single-phase ζ_(a) phase such that said sputteringtarget body is of a structure capable of being subjected to DC magnetronsputtering for forming a βFeSi₂ thin film on a substrate and such thatsaid sputtering target body enables application of a stable bias currentto the sputtering target body during a sputtering operation, enablesplasma density to be readily increased during a sputtering operation,and enables sputtering gas pressure to be kept low during a sputteringoperation; said magnetron sputtering target body having a content ofoxygen as a gas component of 600 ppm or less and a relative density ofat least 95%, and said target texture having an average crystal grainsize of 150 μm or less; and said magnetron sputtering target body beinga sintered body having a diameter of 125 to 300 mm and a thickness of 5mm and having a sputtering face surface ground with a flat-surfacegrinding machine.